1. Field of the Invention
The present invention relates to a method and apparatus for detecting an object and, more particularly, to a method and apparatus for detecting a moving object by using a perspective plane.
2. Discussion of the Related Art
With the recent development in the image processing technology, various types of image processing devices are under research and development. Particularly, such image processing devices may include a function of detecting a moving object within the image. More specifically, a function of detecting a moving object within an image under surveillance by using a visual surveillance device and tracking and displaying the detected object is technically under development. For example, a closed-circuit television (CCTV) is the most typical and widely known and used visual surveillance device. Herein, the surveillance devices are used for diverse purposes, such as preventing crimes including theft and illegal trespassing and also protecting individual privacy.
However, in the related art surveillance device, a moving object is simply detected from the background scene without considering the characteristics of the scene requested for surveillance (hereinafter referred to as a ‘background scene’). Therefore, the related art surveillance device is disadvantageous in that an optimal surveillance cannot be performed or provided.
The problems found in the related art surveillance device and the technical objects of the present invention will now be described in detail with reference to FIG. 1. As shown in FIG. 1, a road allowing vehicles 101a and 102a to pass through is shown as the background scene 10. Generally, a camera (not shown) obtaining the background scene of the visual surveillance device is positioned in a fixed location. Therefore, a perspective view may eventually exist between a close area and a distant area. For example, even when two vehicles 101a and 102a correspond to the same size, it is apparent that the size of each vehicle being filmed within the background scene may be displayed differently due to the perspective characteristic.
In case of the related art visual surveillance device, a minimum size of the object requested to be detected within the background scene is determined. Generally, the related art visual surveillance device performs a filtering process of disregarding any object smaller than the determined minimum size. As described above, the filtering process is efficient for preventing a system overload from occurring in case objects of all sizes are to be detected within the background scene.
In case the perspective becomes deeper due to the characteristics of the background scene, if the size of an object shown at a very far distance is smaller than the predetermined minimum size, the related art visual surveillance device may not be able to properly detect corresponding object. For example, as shown in FIG. 1, when the minimum size of an object that is to be detected is set as area 101, vehicle 101a may be detected, whereas vehicle 102a shown to have the size of area 102 may not be properly detected.